


Fraternal Attraction

by ZairaA



Series: Summer Pornathon 2015 [3]
Category: Merlin (TV)
Genre: Age Difference, Alternate Universe - Modern Setting, Half-Sibling Incest, M/M, Sharing a Bed
Language: English
Status: Completed
Published: 2015-09-01
Updated: 2015-09-01
Packaged: 2018-04-15 15:05:08
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 754
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4611255
Author URL: https://archiveofourown.org/users/ZairaA/pseuds/ZairaA
Summary: <blockquote class="userstuff">
              <p>
  <i>Merlin is only his half-brother, but they've always been close. Then Arthur went to study abroad, and now everything is different. </i>
</p>
            </blockquote>





	Fraternal Attraction

**Author's Note:**

> Winning entry for Challenge four: Forbidden
> 
> Merlin is 16, Arthur is 21
> 
> As always, all the love and gratitude to my awesome beta asya! <333

The day is hot as fuck. Arthur is nursing a beer in the shade, watching from behind mirrored sunglasses while his little brother splashes around in the pool. Merlin has grown tall in the past year, but he's still lean as a whip, and the waistband of his swimming-trunks clings precariously to his hipbones.

Arthur really should stop looking.

Merlin is only his half-brother, but they've always been close. Then Arthur went to study abroad, and everything changed. Closing his eyes, Arthur tries to picture his cute baby brother who followed him around like a puppy, but all he can see are sharp cheekbones, long limbs and dusky nipples...

He jerks up when a heavy weight lands on top of him and he's splattered with water as Merlin shakes himself like a dog. He's laughing, mouth wide open and eyes glittering with mirth and something else - a dare, maybe, but Arthur can't quite tell.

''Get off me!'' he grunts, pushing at Merlin half-heartedly.

Merlin just grins and pins him down, his hands on Arthur's shoulders, and Arthur has the sudden, insane urge to lick the stray drops of pool water from Merlin's chest, to slide his hands into those wet trunks and pull them down over the swell of his brother's arse, touch the water-cool skin.

Arthur's cock stirs and he excuses himself, hastily fleeing inside.

 

\---

That night, Arthur lies awake in his old room. It's still hot, but the thunder in the distance already heralds the approaching storm. Under the thin sheet, Arthur's cock lies full and heavy against his stomach, but he won't touch himself. Not when the only thing he can think of is to strip his little brother naked and stretch him out on this bed, to find his cock and suck it to hardness before diving deeper to kiss and lick at his small private hole.

The first drops of rain clatter against the window, and a flash of lightning illuminates the room. Arthur freezes when he sees Merlin standing in the doorway, watching him.

''Can I sleep here?''

As a boy Merlin always came crawling into Arthur's bed when there was a storm and he was scared.

''Don't you think we're too old for that?''

''Please.''

Merlin bites his lip, and suddenly he's Arthur's cute baby brother again.

''If you hog the blankets, I'll kick you out.''

Only when Merlin climbs in and snuggles back against him, does Arthur realise what a truly bad idea this is. He lies there, tense with fear and arousal. Merlin's unruly hair is tickling his nose, and his erection is brushing against his brother's arse. There's nothing between them but two thin layers of cotton.

''You can, you know?"

"W-What--?"

"I've practised. I can get three fingers in.''

Blood rushes in Arthur's ears and down to his cock. He thinks he might faint. Or come in his pants. Both seems just as likely.

''I've been wanting you to do it since forever, but I knew you'd think I was too young.''

''I'm not-- you're my brother!'' Arthur hisses.

''Half-brother!'' Merlin insists. ''And what does it matter?''

It matters, Arthur wants to snap, but there's a hand inside his boxers, clumsily wrapping around him, and it's the hottest thing Arthur has ever felt. He needs to stop Merlin, but he's paralysed with want and indecision.

Merlin pulls him out and Arthur's cock slides between his brother's cheeks, wet and slippery. Oh god. Merlin has been busy. Has lubed and stretched his hole so that Arthur can fuck him.

Because that's what he wants.

Merlin, that demanding little brat, rocks backwards and Arthur's cock hits the target, stretching that tight pucker the slightest bit.

Merlin moans.

''Arthur... come on... just a little. Just the tip. I want you to."

Letting out a strangled sob, Arthur pushes forward, and then he's inside Merlin and, oh, it's so much more than just the tip, because he can't help but sink further into the tight heat of Merlin's arse.

''We can't...'' he mumbles against Merlin's neck. ''We can't.''

Merlin doesn't answer, instead he takes Arthur's hand and guides it between his legs. Merlin's cock is hard and soft like velvet, and Arthur starts stroking it, mesmerized, keeping in rhythm with his own helpless thrusts.

Arthur comes inside his brother, Merlin's own release sticky on his fingers, exhausted and stunned and close to tears. Merlin turns around.

''Stop freaking out,'' he whispers, pressing a soft kiss against Arthur's lips. ''You know I love you, right?''

Yes, Arthur knows.


End file.
